Restore the Chesapeake

摘要

The most ambitious project ever launched in the United States to restore a polluted estuary and its tributaries is approaching a critical midpoint assessment next year. This is the implementation of the Total Maximum Daily Load established under the Clean Water Act for the entire Chesapeake Bay watershed. A TMDL is the maximum amount of a pollutant that can be discharged to a waterbody from all sources combined and still meet water quality standards. Virtually all of the Chesapeake Bay is in violation of one or more water quality standards. The bay watershed covers 64,000 square miles in parts of six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of Columbia, referred to collectively as the Bay States. The population in this region is 17 million and growing. The restoration effort by the federal Environmental Protection Agency and the Bay States began over 30 years ago, when it was recognized that excessive discharges of nitrogen, phosphorus, and sediment were causing extensive damage to fish, blue crabs, oysters, and other aquatic organisms, as well as numerous plants, birds, and other animals living in the watershed. The effort went into high gear in December 2010, when EPA issued the TMDL.